A somehow failed experiment

[Slawomir]

Hi all,

This imaging season I have been trying to do a few things in a bit different way, and with mixed results. For example, I was quite pleased with my attempt at the Lagoon (https://www.astrobin.com/full/411375/E/), but pure 100% narrowband Trifid (https://www.astrobin.com/full/417063/C/)was a bit of a let down.

While working on my first HaRGB (https://www.astrobin.com/full/421289/0/) image which is yet to be completed, I thought of making an attempt at revealing a tad more of the Helix. I already had 50 hours of Ha at f4.5 from last year, so I just added another 50, but this time at f6, also with my trusty 4" guidescope.

A link to astrobin: https://www.astrobin.com/full/1qk9l2/0/

In spite of making a few attempts at putting the data together, somehow I cannot show more than what I already had last year, and I do not want to overstretch the data because IMO my overstretched Helix always looks plain ugly and flat. Perhaps the subs were too short and I should have gone for 30-minute subs or longer.

Anyway, on top of now accumulated 101 hours of Ha, I already have 30 hours of NII and 20 hours of OIII from last year, so may as well go all the way and try adding some SII to the mix and see what I will manage to cook up with all four :question:

Thank you for looking
Suavi

[Ryderscope]

Whilst you may feel that you have not made prof progress Suavi, there is still an incredible amount of detail in that Ha image. I admire your dedication to the task at hand.

[Atmos]

I'm not sure that going with longer exposures will make much difference. Going longer will only help if you're not already read noise limited, there is a real chance that you're simply aperture limited at your guide scope just doesn't have the light gathering power to suck up any more faint photons.

At 100 hours of Ha, I think the result is what you're gonna be left with.... Which is EPIC!

[ChrisV]

That's really nice. You're getting more than me. I've got 40hours on the Helix with OSC and duo filter and it's not bringing out the detail you have.

[dave_galera]

I think what you have is enough as the outer shell is showing up very very well, which is something you don't often see

[Placidus]

That's the best set of outer chevrons we've ever seen. It's interesting to work out the photons per pixel per hour for some of those faintest details, which look quite grit-free in your image.

We agree that it's technically impossible with an 8 bit screen to show both the outer details and the "eye" without making it look flat. The fault is with the manufacturers of computer screens. We need 16 bit OLED screens.

Superb.

[Slawomir]

Thank you Rodney. Your feedback is much appreciated.



Thank you for your encouragement Colin. Yes, I may actually need a larger aperture. One day...



I thought your attempt at the Helix is fantastic :thumbsup:



Thank you Dave - I was dreaming of showing those shockwaves a bit more clearly.



Thank you Mike and Trish. I use your Ha Helix as a benchmark, as your Helix shows everything so well - data and processing both are top notch.

I think I previously estimated that the outer shockwaves register only one photon per pixel per hour of exposure with my 4" guide scope-camera combo, but will check that estimate later.

Maybe I should chuck in another 50 hours of Ha with longer subs :question: Just as a modification to the original experiment :lol:

[Andy01]

As mentioned elsewhere, that's an outstanding result Suavi, even deeper than my previous effort and the extra integration time has yielded some wonderful extra details.

Top stuff! :thumbsup:

Anxiously awaiting lurid Suavification in colour :lol:

[LewisM]

Failed. Yes Suavi, it's awful. Terrible. Waste of 100 hours. You should permanently delete all this data. Geez, I wouldn't even show this here at all. Embarrassing.

Please, delete - for the sake of humanity - all the data. NOW!

Wasze biczowanie jest głęboko dramatyczne. Zdjęcie jest niesamowite. :)

[multiweb]

As Mike said, best rendition with the depth of the chevrons. One for the cool wall. :thumbsup::thumbsup::thumbsup:

[Benjamin]

Amazing Ha. Curious what 20 hours of O3 looks like? I imagine this is just the central area with its radiating spikes but perhaps there’s more?

[Slawomir]

Thank you Andy, Lewis, Marc and Ben.

@Ben - Yes, the OIII is most prominent around the central white dwarf and with some streamers/spikes streaming out.

@Marc - Thank you Marc for your kind feedback. Perhaps I was expecting too much of an improvement in the data with extra 50 hrs.

@Lewis - Nobody is doing any :evil2: over here ;), but more seriously, I was really expecting a more noticeable improvement.

@Andy - we shall unleash the artist within with the coloured version then :painting::eyepop::scared3:

[multiweb]

Well, seeing what you've got at the 100h mark I'm thinking there's bugger all chances to get much more with that rig by even doubling the time. Convinced me that you need a RASA or hyperstar setup to go any deeper and stay practical with integration time. I tried from home (http://www.iceinspace.com.au/forum/showpost.php?p=1335994&postcount=1) but was limited by skyglow after 25h and that was with 7nm. You hit it with 3nm. There's no hope for us all. :lol: Next time I try it I'll block 1 week somewhere very dark and keep at it.

[Slawomir]

Thank you again Mike and Trish.

The faintest distinguishable bits in the long bows/shockwaves are just 1 ADU above the floor (this is an average for a number of pixels on those fainter parts of the long bows).

Since my camera's gain is 0.16e per ADU, therefore one registered photon makes an increase of 6 ADUs, unless I got it the wrong way around.

Since the image is a result of combining 15 and 20-minute subs, it seems that there is one photon per 1.5 to 2 hours of exposure that are being registered by this telescope-camera combo and that we can just notice in the total of 101 hours of integration.

Quite fascinating, given that we are taking amateurs having fun from their backyards. Or my maths is incorrect :lol:

[Slawomir]

That's a very deep Helix Marc :thumbsup: You are now tempting me - I keep dreaming of an F/3 10" quality Newtonian...

[multiweb]

Even an 8" F/4 would be faster than your refractor and still relatively easy to collimate.

[Bart]

Crikey, that is outstanding! You want more? Wow!

[strongmanmike]

Hmmmm? I'm not quiiiiite sure how one would use the word fail in any sentence describing this image....:question: :shrug:

Errr?...ok..."This image failed to be just another Ha Helix shot" :D" or "This image failed to render me unconscious....I merely fainted" :lol:

:thumbsup:

[gregbradley]

A stunning image Suavi. Hard work to get there I know.

Not to rub it in but my CDK17 with a .66X reducer got similar detail in under 5 hours!

But its an interesting exercise to know what the effect of aperture is on overall exposure time.

Greg.

[Slawomir]

But who said I like it easy :lol:



Glad you like it Bart :thumbsup:



Thank you Mike - perhaps I over-dramatized a bit...:lol:



Thank you Greg. Is this (https://pbase.com/gregbradley/image/136352364)the image you are taking about? I can quite easily see much more faint detail in the image taken with my guide scope :P

[strongmanmike]

..I recon you where just being facetious and a smart arse, knowing full well it was a hum dinger of an image ;) :thumbsup: :rofl:

Mike

[RobF]

Diminishing returns to be expected Sauvi, even with this much data. You'd have to keep doubling to see much improvement?

However, as many others have said, its a stunning image. Definitely NOT a fail!

[codemonkey]

Sensational, Suavi. A monster effort. Yes, you've clearly made it well into diminishing returns but at least you can be confident that you've squeezed as much out of this one as you can with your rig / skies.

And here I was being (a tiny bit) proud that I finally cracked 20hrs of data on one target. Ha.

[RobF]

We're going to need a badge for the Ice in Space avatar - anyone who has imaged a target > 100hrs gets the badge of honour! ;):)

[gregbradley]

Thank you Greg. Is this (https://pbase.com/gregbradley/image/136352364)the image you are taking about? I can quite easily see much more faint detail in the image taken with my guide scope :P[/QUOTE]

No this one:

https://pbase.com/gregbradley/image/150551764/large excuse the over the top colour. Yours probably has finer and a bit more detail but the point really is the power of aperture on imaging time.

Greg.

[bigjoe]

Ohhh nonsense Suavi, its so full of detail and depth...no need to feel its anything but superb.
Bigjoe.

[Slawomir]

:lol: But I honestly was disappointed at first. Promise.



Thank you Rob :thumbsup:



20hrs is heaps, especially when a skilled astrophotographer like you processes the data :thumbsup:



That would be nice :)



No this one:

https://pbase.com/gregbradley/image/150551764/large excuse the over the top colour. Yours probably has finer and a bit more detail but the point really is the power of aperture on imaging time.

Greg.[/QUOTE]

Love the colours Greg. I agree that aperture helps, but I still think that my 24hr simple stack n stretch (https://cdn.astrobin.com/thumbs/Rc9jz0ZaWmbN_16536x16536_kQt6vfvn.j pg) shows more of the faint stuff, which is a bit surprising, given that your 17" collect nearly 20 times as many photons as my 4" :question:



Glad you like it Joe.

[strongmanmike]

Ha!....closely followed by the sliiightly deeper Placidus Observatory 72hr effort (:prey2:), overall, it's probably the best Ha image of the Helix I've seen :thumbsup:

Mike
becoming an unashamed Coleslawomir fanboy....:P

[rustigsmed]

looks nice and smooth to me Suavi, great dedication!

Russ

[Peter Ward]

I have 40 hours of h-alpha Helix data taken with my 305mm F3.8 AP-honders....(back of the envelope...about 270 hours worth through a 4 inch aperture)

But I didn't get the same level of detail in the faint chevrons....

Don't know how you do it. Your star sizes are even smaller than M&T's 20" CDK data.

Quite amazing really.

[Slawomir]

Thank you very much for such nice feedback and encouragement Mike, Russ and Peter.

I think if I used a 5nm instead of a 3nm Ha filter, I would have gotten a good SNR a tad sooner. Overall not bad for a 4" from a tropical coastal town.

Bad news is that my PC with all Helix data has died last night - hopefully the hard drive is okay, as I have not backed all of the data :sadeyes:

While the PC is being repaired, I started collecting SII last night. Not much signal in there, but will try to get a few nights worth of SII. The Helix is right next to the bright one in the sky over the next week, so may need to wait a bit and hopefully the skies will remain clear in the coming weeks, as well as my data will hopefully get recovered from the malfunctioned PC :prey:

[Atmos]

That doesn’t sound good at all Suavi :/
I had a similar scare last year and lost a bit of data off my first backup drive but managed to recover most of the data.

[strongmanmike]

Oh crap! :eyepop:...fingers crossed :prey: :thumbsup:

Mike

[Paul Haese]

Well that is deeper than my Ha effort of 50 odd hours. Those very outer chevrons are well defined in your image, not so in my data. I would say 50 hours more makes a significant difference Suavi. If you like you can use my data to add to yours. Mine is from my FSQ.

On my screen the lower area is just showing too. I would imagine there is more detail lurking there. Another another hundred hours and that is going to be one hell of an image. Outstanding image of this target with the current 100 hours.

[Slawomir]

Thank you Paul for your feedback and a very kind offer - my PC with all of the Helix data is being repaired, so at the moment I'm just waiting for the news, good hopefully. It would be interesting for sure to see what can be squizzed out of the combined 4" data.